1. Field of the Invention
This invention relates to indicator devices associated with celestial mechanics and, more particularly, to an indicator that provides an easily understood graphic display of the angle between the solar radiant vector and the plane of orbit of an artificial earth satellite (beta angle). Utilizing an earth-centered universe fiction, the device illustrates causes and effects of beta angle variation through seasonal variations of earth's position about the sun and for different conditions of orbit creation (viz. time of year, time of day at launch and location of the launch site).
Since appreciable numbers of future space missions will depend on solar panels of photo-voltaic arrays for operational power, planning of such missions must include availability of solar energy, earth eclipse periods and other features affecting the same. Similarly, studies of deep galactic points of interest will depend on uninterrupted line of sight access to the same by means of telescopes, antennas and other highly directional equipments. Planning for this latter type mission is also facilitated by the within device.
2. Description of the Prior Art
Many two and three dimensional models of our planetary system are available for educational presentation of solar system geometry and the relationship between planets of our solar system. No such models are available for presentation of the relationship between artificial earth satellite orbital planes and the solar radiant vector, as is available from the within invention. It presents a clear, visual display of the effect of seasonal changes in the earth's position, in its orbit around the sun, upon established orbits of artificial earth satellites. Wide-spread use of such satellites for communications, mapping, natural resource management and earth surveillance has created a need for such an easily understood, reasonably priced indicator.
A variety of transparent plastic spheres with star patterns, planetary orbit references and complicated control and suspension means are available to represent certain features of artificial earth satellite operation, but cost, complexity and lack of availability preclude their general use. We are not aware of the existence of a device relating earth satellite orbital planes to both earth's solar vector and to the galactic plane as does the within device.